Life is Better With Tankless

Need help understanding what tankless water heaters are and if they’re right for you? We’re here to help. We have everything you need to make an educated decision on your home’s most important appliance.

How Tankless Works

No-Hassle Hot Water, When and Where You Need It

With a tankless water heater, your home's cold water is heated only when you need it, and it stays hot until you're done using it. This results in a limitless hot water supply and little to no wasted energy usage.

  1. Flame ignites and heats two heat exchangers
  2. Water preheats as it passes through the secondary heat exchanger
  3. Water continues to heat to desired temperature as it passes through stainless steel primary heat exchanger
  4. Water exits the unit and travels to the water fixture where it is needed
  5. Flame output adjusts as needed to maintain water temperature during use
  6. With usage complete, the flame turns off and water stops flowing

Tankless water heaters can work with both natural gas and propane heat sources.

If your home runs on all-electric heat, tankless may still be a viable option. Contact a Rinnai PRO for further assistance.

Condensing vs. Non-Condensing

RX/RXP Series


The most advanced Condensing Tankless Water Heater on the market sets the standard for efficiency.

  • Highest efficiency available up to a 0.98 UEF for RXP models.
  • Industry first WiFi connection with smartphone via Bluetooth®.
  • All-in-one easily install indoors or outdoors using natural gas or propane.
  • Ideal for colder climates with lower groundwater temperatures
RE/REP Series


The FIRST and ONLY Non-Condensing Tankless Water Heater, REP Models, with a built-in pump.

  • Lower initial cost, though you need a metal-based exhaust vent system
  • Simpler maintenance
  • No need to drain condensate if vented horizontally
  • Ideal for warmer climates with higher groundwater temperatures

Technology & Features

  1. 01

    Compact Size

    Tankless water heaters are about the size of a carry-on suitcase, so they can fit in small spaces like closets, cabinets, and mud rooms.

  2. 02

    Unlimited Hot Water

    Because your water is continuously heated as needed, you’ll never have to choose between taking a hot shower, doing a load of laundry, or running the dishwasher.

  3. 03

    Wi-Fi Capable

    Wi-Fi technology allows certain water heaters to be monitored and controlled (scheduling, recirculation, and more) by our Rinnai Central™ mobile app via smartphone or voice-controlled device (module purchased separately).

  4. 04


    Tankless water heaters are easier to repair than tanks, often eliminating the need to replace the unit. And many offer extended, comprehensive warranties.

  5. 05

    Energy Efficiency

    Rated by a Uniform Energy Factor (UEF), tankless water heaters are a highly efficient hot water appliance and ENERGY STAR® certified units offer additional energy saving benefits.

  6. 06


    Smart-Circ™ Intelligent Recirculation™ learns your hot water usage pattern and schedules recirculation accordingly to provide you with faster hot water when you need it.

The Smart Investment

RX Series

Better Than a Tank

Your water heater is the most important appliance in your home. Choosing tankless is the smart investment.

  • Tankless water heaters last up to twice as long as tanks
  • Save energy by heating water only when it's needed
  • Avoid costly replacement events with a maintainable and repairable tankless unit

Compare Tankless vs. Tank

Tankless Water Heater Storage Tank Water Heater
Technology Condensing
50G Tank
50G Tank
Fuel Type or Energy Source Natural Gas Propane Natural Gas Propane Natural Gas Propane Electric
UEF (Uniform Energy Factor) 0.98 0.97 0.82 0.81 0.60 0.60 0.95
Annual Operating Costs* $201 $487 $228 $552 $309 $745 $626

*As based on the average cost to run an electric tank water heater per the Department of Energy (DOE) Average Energy Costs ( 2017

Find the Right Rinnai For Your Home

Answer a series of simple questions about your home and our Solution Selector will show you exactly what Rinnai system you need to improve your life and home.

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Protect Your Investment

Tankless water heating system installs require a specific knowledge and highly trained skill set you can only get from a professional. Be sure to protect your investment by having your tankless system installed by a certified Rinnai PRO.

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Professional Installation Recommended

Ready for more? Visit our tankless water heater page for deeper information.